import pygame

from pygame.sprite import Sprite

class Bullet(Sprite):
    
    def __init__(self, ai_settings, screen, myball):
        super().__init__()
        self.screen = screen

        
        self.rect = pygame.Rect(0, 0, ai_settings.bullet_width, ai_settings.bullet_height)
        self.rect.centerx = myball.rect.centerx
        self.rect.top = myball.rect.top
        #储存用小数表示子弹的位置
        self.y = float(self.rect.y)

        self.color = ai_settings.bullet_color         
        self.speed_factor = ai_settings.bullet_speed_factor 
        
    def update(self):
        self.y -= self.speed_factor
        self.rect.y = self.y
    def draw_bullet(self):

        pygame.draw.rect(self.screen, self.color, self.rect)

        

        
